Before forming, pre-star 'cloud clumps' have generated no stellar winds -- instead of driving material away, through radiation pressures, they are still accreting material. But, once fully formed, after "first light", MS stars start shedding material, driving out stellar winds, that blow out 'astro-sphere' bubbles. Could, therefore, you not infer the age of a star, since it arrived on MS, by the size, of its ever-expanding astro-sphere ?

no, because it is not ever expanding.

 

there are interstellar winds that limit the size and its size can grow and shrink (it has passed over both of voyager proves several times IIRC)

Couldn't there be qualitative correlations, between "young immature" astro-spheres; and "old mature" astro-spheres? In the extreme, young T-Tauri stars are still shrouded in their 'Bok Globules' & 'E.G.G.s', w/ no AS's to speak of; whereas, older MS and post-MS stars, having 'evaporated' from their initial birth clusters, have full-flowered AS's.